نتایج جستجو برای: zsm 5 zeolite
تعداد نتایج: 1223385 فیلتر نتایج به سال:
A new kind of organosilane (1,6-bis (diethyl(3-trimethoxysilylpropyl)ammonium) hexane bromide) with a geminitype structure was prepared and used as a mesoporogen for the synthesis of hierarchical porous ZSM-5 zeolite. There are two quaternary ammonium centers along with double hydrolysable -RSi(OMe)3 fragments in the organosilane, which results in a strong interaction between this mesoporogen a...
Optimizing the number, distribution, and accessibility of Brønsted acid sites in zeolite-based catalysts is of a paramount importance to further improve their catalytic performance. However, it remains challenging to measure real-time changes in reactivity of single zeolite catalyst particles by ensemble-averaging characterization methods. In this work, a detailed 3D single molecule, single tur...
A Cu-doped zeolite ZSM-5 (Cu-ZSM-5-M) with a micro-meso-macroporous structure was directly synthesized, and it exhibits excellent catalytic activity and good recyclability in the cross-coupling of aryl halides with diphenyl disulfides. This feature should be attributed to the structural characteristics of meso-macropores and homogeneous dispersion of active Cu(δ+) (δ < 2) species in Cu-ZSM-5-M.
Due to crude oil is limited, new resources for fuel and petrochemicals are important to be developed. Biogas or NG (Natural Gas) can be easily converted into methanol which can be reacted over zeolite to produce olefins and gasoline. HZSM-5 zeolite catalyst has been used in this study and its modification by (0.5wt%, 1wt%, 2wt% and 4wt %) Ni to convert methanol to hydrocarbons (MTH). Catalysts ...
We report the one-step synthesis of a highly active hierarchical Fe/ZSM-5 zeolite catalyst with a strongly improved lifetime in the selective hydroxylation of benzene to phenol with nitrous oxide; compared to the best Fe/ZSM-5 catalyst, the turnover number after 24 h on stream is almost four times higher.
Fe/ZSM-5 nanosheet zeolites of varying thickness were synthesized with di- and tetraquaternary ammonium structure directing agents and extensively characterized for their textural, structural, and catalytic properties. Introduction of Fe3+ ions in the framework of nanosheet zeolites was slightly less effective than in bulk ZSM-5 zeolite. Steaming was necessary to activate all catalysts for N2O ...
The selective preparation of monobenzyl glyceryl ethers, which are potential commodity chemicals with special functions, was explored to find new applications for glycerol. Among the acid catalysts investigated (sulfuric acid, heteropoly acid, Nafion(R), and zeolite), Zeolite Socony Mobil-5 (ZSM-5) afforded better results. The reaction of equimolar amounts of glycerol and benzyl alcohol at 150º...
A new catalyst comprising cerium and silver ion-exchanged ZSM-5 zeolite is reported in this paper, for the reduction of nitric oxide by methane in the presence of excess oxygen. The bi-cation exchanged Ce-Ag-ZSM-5 catalyst was very active for this reaction, while either Ce-ZSM-5 or Ag-ZSM-5 alone showed low activity. The presence of oxygen in the feed gas mixture enhanced the activity of the ca...
Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50-150 μm-sized FCC spheres heavily influence their catalytic performance. Single-molecule fluorescence-based imaging methods, namely nanometer accuracy by stochastic chemical reactions...
The structure and reactivity of a room temperature stable zinc carbonyl complex in Zn-modified H-ZSM-5 zeolite were revealed by solid-state NMR spectroscopy.
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